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Tombstone exhausted ObjectIds in the wire 

It's possible though unlikely to overflow the generation for a given
ObjectId. If this happens, an object like a Buffer or Fence could begin
receiving callbacks for previously destructed objects. This CL makes it
so the client doesn't reuse ObjectIds once they've hit the max generation
number so overflow isn't possible.

Bug: dawn:381
Change-Id: I443c1c87d96614a95d1973e2bf18cd702c34b3f9
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/19240
Commit-Queue: Austin Eng <enga@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
This commit is contained in:
Austin Eng 2020-04-13 17:11:22 +00:00 committed by Commit Bot service account
parent 3c31efc796
commit 077a427499
1 changed files with 11 additions and 5 deletions
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16
src/dawn_wire/client/ObjectAllocator.h
View File

@ -16,6 +16,7 @@
#define DAWNWIRE_CLIENT_OBJECTALLOCATOR_H_
#include "common/Assert.h"
#include "common/Compiler.h"
#include <memory>
#include <vector>
@ -46,24 +47,29 @@ namespace dawn_wire { namespace client {
ObjectAndSerial* New(ObjectOwner* owner) {
uint32_t id = GetNewId();
T* result = new T(owner, 1, id);
auto object = std::unique_ptr<T>(result);
auto object = std::make_unique<T>(owner, 1, id);
if (id >= mObjects.size()) {
ASSERT(id == mObjects.size());
mObjects.emplace_back(std::move(object), 0);
} else {
ASSERT(mObjects[id].object == nullptr);
// TODO(cwallez@chromium.org): investigate if overflows could cause bad things to
// happen
mObjects[id].serial++;
// The serial should never overflow. We don't recycle ObjectIds that would overflow
// their next serial.
ASSERT(mObjects[id].serial != 0);
mObjects[id].object = std::move(object);
}
return &mObjects[id];
}
void Free(T* obj) {
FreeId(obj->id);
if (DAWN_LIKELY(mObjects[obj->id].serial != std::numeric_limits<uint32_t>::max())) {
// Only recycle this ObjectId if the serial won't overflow on the next allocation.
FreeId(obj->id);
}
mObjects[obj->id].object = nullptr;
}